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Direct analysis of scaling violations in large- Q 2 deep-inelastic neutrino and muon scattering

1983; American Physical Society; Volume: 27; Issue: 3 Linguagem: Inglês

10.1103/physrevd.27.508

1538-4500

A. Devoto, Dennis W. Duke, J. F. Owens, Richard G. Roberts,

Quantum Chromodynamics and Particle Interactions

We have made an extensive analysis of all large-${Q}^{2}$ deep-inelastic neutrino and muon scattering data using evolution equations to fit the scaling violations directly at fixed Bjorken $x$. We have included all higher-order corrections in both the nonsinglet and singlet cases. We find that the nonsinglet neutrino data give ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}\ensuremath{\simeq}300\ifmmode\pm\else\textpm\fi{}80$ MeV but with systematic uncertainties of at least 100 MeV ($\stackrel{-}{\mathrm{MS}}$ refers to the modified minimal-subtraction scheme). The singlet neutrino and muon data are equally consistent with either ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}\ensuremath{\simeq}200\ifmmode\pm\else\textpm\fi{}100$ MeV and a soft gluon distribution or ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}\ensuremath{\simeq}350\ifmmode\pm\else\textpm\fi{}100$ MeV and a hard gluon distribution. Values as low as ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}\ensuremath{\simeq}100$ MeV found in previous analyses are likely to be spurious.